1. Field of the Invention
The invention relates to a method and device for removal of diseased tissue for disposal or analysis.
2. The Prior Art
A Lateral Biopsy Device is shown in U.S. Pat. No. 5,653,240 and a device and method for Serial Collection, Storage and Processing is Described in U.S. Pat. No. 5,980,468, both which are hereby incorporated reference. These references disclose techniques for removing tissue by cutting, coring and scraping. The tissue is cut, captured, stored and removed for analysis or disposal from sites deep within body cavities. The tissue is taken from approached long paths to organ lumens as in the gastrointestinal, pulmonary, urological, gynecological, neurological or vascular systems. These methods are useful in many medical applications with modifications appropriate to the specific disease and diagnostic or therapeutic purpose.
An object of the present invention is to provide for removal or ablation of diseased tissue for restoring a stenotic or occluded lumen to patency. In the process of the present invention, the diseased tissue is captured within a cone tip or a tube shaft of a lateral biopsy device and retrieved for disposal or analysis. This allows for analysis of serial specimens of tissue to determine the completeness of removal as in ablation of a malignancy or removal of plaque in blood vessels. When removing occluding plaque within a blood vessel, storage and retrieval prevents distal embolization of fragments that would occlude smaller distal blood vessels.
Removal of obstructing tissue within a blood vessel lumen requires traversing the vascular lumen leading to the obstruction, passing through the obstruction and coring or scraping the obstructing material into the head or shaft of the lateral biopsy. Traversing a vascular lumen over a guide wire is a standard medical technique. The wire guided lateral biopsy is modified according to the invention by replacing the filiform leader and wire actuator with a central plastic tube attached to the perforated cone blade tip that passes over the previously inserted guide wire. The cone blade tip must pass the obstruction as a dilator or be compressed to traverse the stenosis and expand to serve as a cutting device or an anvil for a shaft blade. Many obstructing lesions are elastic. They compress to allow dilator passage only to reexpand and obstruct. For these lesions the cone tip serves as both a dilator and a cutting device or an anvil. In more rigid lesions, as in peripheral vascular obstructions, the cone dilator must be compressible with a flower petal configuration. The compressive force of the rigid lesion and the catheter shaft traversing the guide wire closes the petals of the cone traversing and dilating the stenosis. The catheter tube shaft blade is then advanced to meet the cone and cores off the obstructing tissue into the shaft.
Alternatively, the backward facing cone blade may be pulled back with the central tube and the obstructing tissue captured within the cone tip. For long lesions, as in peripheral arteries, a shaft blade with shaft capture provides a large storage space for cored tissue. A preferred embodiment would have a diameter range of 3 to 10 mm. For short lesions, capture in the tip is sufficient and allows a smaller more flexible lateral biopsy device suitable for smaller arteries 2-3 mm in diameter, such as in the heart. This would be particularly useful for eccentric soft lesions in the coronary arteries. A preferred diameter for these lesions is 2 to 4 mm.
For eccentric lesions, the cone blade is modified to have the cutting blade in a specific quadrant allowing removal of the visible lesion with protection of the opposite side of the lumen. This is accomplished by using a radiolucent plastic tip with a radiopaque blade inserted into a segment of the cone. More rigid calcified tissue can be removed by adapting the coring surfaces through a rotating saw blade or abrasive hardened surface. Either rotational or vibrational forces are applied to the blade through a central tube wire lumen of the cone blade tip or by rotating the tube shaft of the shaft blade.
In another preferred embodiment, the cutting surface is in the shaft and the cone tip serves to prevent downstream loss of cored material until the tip and shaft close. To close the apparatus, the apposition of the shaft and tip capture the free material in the shaft lumen preventing loss while the instrument is withdrawn. This is an important feature to prevent distal embolization of the cored material in the vascular system.
Removal or ablation of neoplastic tissue by cutting, coring or scraping serves to restore a stenosed lumen and remove debris. Completeness of the removal, i.e. excisional biopsy, as determined by microscopical study of the tissue specimens, obviates the need for other therapy such as traditional surgical excision, radiation or chemotherapy. Early neoplastic lesions may have a long latent period before becoming invasive, symptomatic or metastatic. Therefore, as detection of early neoplastic lesions increases, the need for low risk minimally invasive, cost effective removal increases. The bile duct, pancreatic duct, bronchi and ureter are prone to neoplastic transformation. These lumens are difficult to access and treat by traditional surgical methods but easily accessed by endoscopy. Neoplasms in these areas are ideal for biopsy, excision, or debulking by the methods described here. Additionally, ablation of tissue and sealing of bleeding points would be accomplished by electrical heating or coagulation of the tissue surface performed by passing the appropriate electrical current to the metal cone tip or shaft blade.
After the lumen is enlarged to the diameter of the first instrument and that instrument is removed, leaving the wire guide in place, serial instruments of larger diameter are passed over the wire guide to further enlarge the lumen. Serial instrument passes allow progressive enlargement of the lumen. For example, a blood vessel or bile duct 10 mm in diameter with a 90% obstruction has a 1 mm lumen that allows passage of a 1 mm wire. Passage of a 2 mm diameter coring instrument would be followed serially by a 4 mm, then 6 mm, 8 mm and 10 mm instruments until the original lumen of 10 mm was restored. Each successive enlargement of the lumen would allow passage of a stiffer more efficient coring device followed by exchange for a stiffer wire guide to provide the necessary increase in coring force required by the larger surface area cored. Each pass traverses a path prepared by its predecessor. This is an advantage of the present invention as compared to balloon dilation or passage of concentric dilators that dilate without tissue removal. In these techniques, although the lumen is restored, in part, a large mass of unwanted tissue is displaced laterally rather than removed. Tissue recoil may close the lumen after dilation or the blood vessel rupture. The unwanted tissue may contribute to the frequent blood vessel restenosis. In cancer, the bulk of a compressed residual tumor may cause restenosis and limits the effectiveness of chemotherapy or radiation.
Monitoring is facilitated by radiography with injection of radiopaque contrast or other imaging techniques using the lumen leading to the space between the tip and shaft or the wire guide lumen. In the larger instruments a secondary lumen for contrast injection could be added to the shaft. The injection lumen also allows fluid sampling and pressure measurement.